As both Tokina and Sigma claimed inability to update their old lenses to work with digital Canon bodies I do not trust them any more. This can happen again.
I am new to this. When did this happen?
I bought the Tokina ATX28-70 f2.8 by the year 1993. It worked fine on my EOS600 and EOS620 (and later I found out that it worked fine on EOS1n). When I tried to use it on a EOS50E (1996 or 1997) the camera was blacking out when I pressed the shutter release. Needless to say it does not work with digital bodies too
My old Sigma 14mm - I say old because there was a newer edition of that lens - works ... a little on my EOS5DmkII Only when the aperture is fully open (You can only imagine the vignetting I get! I didn't even care to check the optical quality).
I didn't even know that there was at least a specific usable aperture until I saw at ebay a listing of a very old SIGMA 500mm that was reported to work with analog bodies plus with EOS5DmkII at open aperture (only). That gave me the idea to check my SIGMA lens.
"This lens will only focus on digital cameras like the 5D or 50D and work with an open aperture, you will get an error message if you stop down "